The exceptionally high intrinsic carrier mobility of graphene makes it a potentially promising material for high frequency electronic devices such as, for example, low-noise amplifiers for communication applications. However, there are many applications for nanoscale forms of carbon in which a graphene nanomesh (GNM) might be preferable to a continuous layer of graphene.
GNM may be intrinsically semiconducting with a non-zero gap (unlike graphene that has a zero gap with a vanishing density of states (DOS)), or quasi-metallic like graphene, with a vanishing DOS at the Fermi energy. Existing methods for nanomesh patterning of graphene, however, have drawbacks.
For example, existing approaches are not scalable to large areas. Additionally, in some existing approaches, graphene may be degraded by the deposition and removal of the masking materials used. A drawback of an existing approach in which graphene on a carbide-forming metal (M) layer is patterned by carbide-forming reactions with overlying metal nanodots is the narrow process window for graphene patterning versus graphene re-growth, a consequence of the fact that graphene removal by a carbide formation reaction with the nanodot is reversible via a mechanism in which the metal/metal carbide nanodot migrates into and merges with the M support layer, leaving behind a “healed” graphene surface reformed with carbon released from the nanodot.
Other existing approaches, such as those utilizing mobile metal nanodots for patterning, have disadvantages related to a lack of a means to control the nanodot trajectories (and the patterns of removed graphene left in their wake).
Accordingly, given the disadvantages of the existing approaches, there is a need for improved methods for nanoscale patterning of graphene.